Other Balance Sheet Information - Summary of Account Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Sep. 30, 2019
Valuation and Qualifying Accounts Disclosure [Line Items]
Accounts receivable	$ 183,324	$ 169,317
Less allowance for doubtful accounts	(4,225)	(3,644)
Accounts receivable, net	179,014	165,602
Allowance for Sales Returns
Valuation and Qualifying Accounts Disclosure [Line Items]
Less allowance for sales returns	$ (85)	$ (71)